Tight Against the Horizon

Three planets toy with the sun

By J. Alex Knoll

This week boasts the earliest sunrises of the year, when old Sol crests the horizon at 5:41am. We’re still a couple weeks from solstice, the overall longest day of the year, and the latest sunset won’t come for another two weeks after that. Why? Several reasons, including earth’s not-quite-spherical shape, its elliptical orbit around the sun and the varying point of high noon across the globe.
If you’re up before dawn, look to the northeast for the return of Mars, which has been hidden behind the sun since mid-April. The red planet rises around 5am and doesn’t gain much altitude before the sun comes beating fast on its trail. And at magnitude +1.4, it isn’t particularly bright, so you may need binoculars to pick it out from the pre-dawn haze.
You shouldn’t have that problem spotting Venus at the other side of darkness, low in the west-northwest following sunset. Other than the moon, there simply isn’t a brighter object in the night sky. Venus is so bright, you may be able to see it before sunrise. And once you’ve found Venus, you should have no trouble finding neighboring Mercury less than five degrees higher. Monday the waxing crescent moon shines just a few degrees to the left of Venus, with Mercury above the two forming a nice triangle.
Circling the sun every 88 days, Mercury is hidden from view more often than not. Friday marks the innermost planet’s greatest evening escape of the year, when it hovers 24 degrees above the horizon at sunset. Then it sinks back toward the horizon — and Venus. Watch as the two close the gap over the next two weeks, Venus inching upward to meet its descending neighbor. Ten degrees above the pairing of Mercury and Venus, you’ll find the twins of Gemini, Castor and Pollux, spaced apart much the same as the two planets. Orange-hued Pollux is the brighter star, while blue-white Castor is the star farther north.